Valve for a pressurised dispenser comprising inlet orifices being deformable by the internal pressure

ABSTRACT

A pressurised dispenser valve ( 110 ) has a valve housing ( 111 ) with at least one fluid inlet ( 127, 128 ) though which a fluid present in an associated dispenser may pass to enter the valve housing. The at least one fluid inlet is formed at least partly by, or in a resiliency deformable portion ( 124, 125 ) of the valve housing. The deformable portion ( 124, 125 ) is arranged such that, in use when the valve is opened, it deforms from an initial resiliency biased configuration in which the fluid inlet ( 127, 128 ) has an initial cross sectional area to a deformed configuration in which the fluid inlet has an altered cross sectional area in response to a pressure differential between the interior of the housing and the exterior of the housing. The change in cross sectional area of the inlet can be made to vary independence on the pressure in the canister and can be used to control the rate of flow of the fluid through the inlet as the pressure in the canister falls during use.

This invention relates to a valve for a pressurised dispenser and to a pressurised dispenser having such a valve.

It is known to provide a pressurised dispenser comprising a container or canister in which a product is stored under pressure. A valve is provided to enable the product to be dispensed from the canister when the valve is opened. The product to be dispensed will often be a liquid, such as a liquor for example, and a propellant will also be present in the canister at least partly as a compressed gas. Some propellants, such as butane, are present partly as a gas and partly as a liquid, which may be in solution in the liquid product. Other propellants, such as compressed air or nitrogen, are present only as a gas whilst with propellants such as carbon dioxide a limited amount of the gas may be held in suspension in the liquid. In certain pressurised dispensers, the liquid product is held in a flexible bag within the canister and so is separated from the propellant.

A nozzle is often fitted to the outlet valve by means of a valve stem to ensure the product is delivered in an appropriate form and direction for the application. Many dispensers have an atomising nozzle fitted to the outlet valve, the nozzle being configured to cause a liquid stream passing through the nozzle under pressure to break up or “atomise” into numerous droplets as it passes through an outlet orifice of the nozzle to form an atomised spray or mist. A large number of commercial products are presented to consumers in this form, including, for example, antiperspirant sprays, de-odorant sprays, perfumes, air fresheners, antiseptics, paints, insecticides, polish, hair care products, pharmaceuticals, water and lubricants. In other applications, such as shaving foams, the nozzle is adapted to dispense the product as foam or gel.

Pressurised dispensers which are configured to produce an atomised spray are often referred to as aerosol dispensers though this term is sometimes applied generally to all pressurised dispensers, even those in which the product is dispensed say as foam rather than an atomised spray.

In an aerosol dispenser, the optimum size of the droplets required in the spray depends primarily on the particular product concerned and the application for which it is intended. For example, a pharmaceutical spray that contains a drug intended to be inhaled by a patient (e.g. an asthmatic patient) usually requires very small droplets, which can penetrate deep into the lungs. In contrast, a polish spray preferably comprises spray droplets with larger diameters to promote the impaction of the aerosol droplets on the surface that is to be polished and, particularly if the spray is toxic, to reduce the extent of inhalation.

The size of the aerosol droplets produced by conventional spray nozzle arrangements is dictated by a number of factors, including the dimensions of the outlet orifice(s) and the pressure with which the fluid is forced through the nozzle. However, problems can arise if it is desired to produce a spray that comprises small droplets with a narrow droplet size distribution, particularly at low pressures. The use of low pressures for generating sprays is becoming increasingly desirable because it enables the quantity of propellant present in the spray to be reduced or alternative propellants, such as compressed air, which produce lower pressures to be used. The problem of providing a high quality spray at low pressures is further exacerbated if the liquid product concerned has a high viscosity because it becomes harder to atomise the fluid into sufficiently small droplets.

A further problem with known pressurised aerosol dispensers fitted with conventional valve and spray nozzle arrangements is that the size of the aerosol droplets generated tends to increase during the lifetime of the aerosol dispenser, particularly towards the end of the dispenser's useful life as the pressure within the canister reduces as the contents become gradually depleted. This reduction in pressure causes an observable increase in the size of the aerosol droplets generated and thus, the quality of the spray produced is compromised.

The amount by which the pressure drops over the life of the dispenser varies depending on the type of propellant used. Where the propellant, such as butane, exists in the canister both as a liquid and a gas, the reduction in pressure over the life of the dispenser may be 20-30%. With this type of propellant, more gas comes out of solution as the product is used up and the pressure in the canister drops. By comparison, with propellants that are present mainly or exclusively as a compressed gas, the overall reduction in pressure may be 50% or more.

To assist in the break up of droplets and improve atomisation some known aerosol dispenser valves are arranged so that a small amount of propellant gas is introduced into the liquid product as it is dispensed, either within the valve itself or downstream of the valve in the case of a divided valve in which the liquid and gas streams are kept separate in the valve. The gas is mixed with the liquid and expands when the liquid passes through the outlet orifice of the nozzle helping to break up the liquid into smaller droplets. In one known arrangement, one or more fine holes or openings are provided in the housing of the valve through which the propellant gas can be bled into the liquid product as it is flows through the valve. This is known as a vapour phase tap (VPT).

A problem with the use of a VPT or other arrangement for introducing propellant gas into the liquid as it is dispensed is that the propellant gas is used up more quickly than would otherwise be the case, exacerbating the problems discussed above in regard to the loss of pressure in the canister over the life of the dispenser. This is a problem regardless of the propellant used but is a particular problem where the propellant is a compressed gas, such as air or nitrogen, where the loss of pressure may result in an unacceptable performance as the contents become depleted. For example, in a typical dispenser without a VPT and which uses compressed air as the propellant, the starting pressure will be around 10 bar reducing to around 4 bars. However, if a VPT or other arrangement is used, the pressure may fall to less than 2 bars, which often is insufficient to atomise the liquid. For this reason, known pressurised dispensers having a compressed gas propellant are not usually provided with a VPT.

For the purposes of atomising the liquid product, it is preferable if the arrangement for introducing propellant gas into the liquid product produces a higher ratio of propellant gas to liquid when the pressure in the canister is lower than when the canister is full and the pressure is higher. This is because at the higher pressures, the relatively high rate of flow of the liquid through the nozzle is often sufficient on its own to cause the required atomisation without the need to introduce propellant gas into the liquid stream. However, with a conventional VPT, the opposite effect is seen as the ratio of propellant gas to liquid falls as the pressure in the canister falls. This can be explained by considering the flow through the VPT. The gas flows through the VPT because the pressure inside the valve housing is lower than the pressure of the gas outside of the housing when the valve is open and the rate at which the gas flows through the VPT is a function cross sectional area of the VPT and the pressure difference across it. Because the cross sectional area of the known VPT is fixed, the volumetric flow rate through the VPT reduces as the pressure in the canister, and thus the pressure differential across the housing when the valve is opened, falls.

In order to ensure that sufficient gas is bled into the liquid to provide for proper atomisation of the liquid when the pressure in the canister has reduced towards the end of the life of the dispenser, conventional VPT openings have to be a certain minimum size. However, this means that excess propellant gas is bled into the liquid when the canister is full and the pressure is higher. It can be seen, therefore, that with a conventional VPT arrangement a considerable amount of the propellant gas bled through the VPT when the canister is relatively full is wasted, as it is not essential for ensuring proper atomisation of the liquid. This problem is further compounded because the propellant gas is compressible and hence for a given volumetric flow rate, a greater mass of gas will pass through the VPT when the canister is full and is at its highest pressure than when the canister is nearly empty and the pressure inside the canister has dropped.

To address the above problems, the applicant has proposed in International patent application publication No. WO2006/095153 an aerosol dispenser having a valve comprising a means for introducing propellant gas into the liquid product as it is dispensed and a flow control arrangement arranged to increase the ratio of propellant gas to liquid product dispensed as the pressure in the dispenser decreases over its useful life. Several embodiments for achieving this are disclosed in the application, the content of which is hereby incorporated in its entirety. In a particularly advantageous embodiment, the valve has two flow control mechanisms, one for varying the rate at which propellant gas is bled into the liquor in dependence on the pressure in the canister and a second to control the rate at which the liquid product flows through the valve, also in dependence on the pressure in the canister. The use of two flow control mechanisms in this way allows the ratio of propellant gas to liquid product to be increased in a controlled manner as the pressure in the canister falls.

The flow control mechanisms disclosed in WO2006/095153 comprise an opening in a wall through which the fluid passes and a flow control element in the form of a disc which, when the valve is open, is biased by the pressure differential across the opening against the wall to restrict the flow of liquid through the opening. The disc overlies the opening but is arranged so as not to form a perfect seal with the wall so that the fluid can pass between the wall and the disc to enter the opening. By suitable design of the wall and the disc, it can be arranged that the leakage between the wall and disc varies as the pressure in the canister falls to control the flow rate of the fluid.

The flow control mechanisms disclosed in WO2006/095153 are effective but there is the possibility of them becoming blocked or sticking when used with certain types of liquid product such as polish, hairspray, paint, antiperspirant and the like.

There is a need, therefore, for valve having an improved flow control mechanism to overcome, or at least mitigate some or all of the problems associated with the known flow control mechanisms.

It has also been found that varying the manner in which the gas is delivered into the valve housing thorough a VPT makes a significant difference to the droplet size and to the spray form of the aerosol. In particular, it has been found that using several small VPT holes give better results than one large hole. It is believed that using several small holes encourages the gas and liquid to mix inside the valve housing. However, there are difficulties in manufacturing small holes. Typically, the valve housing is injection moulded from polymeric materials and the VPT holes are produced using pins in the mould. In order to produce smaller holes the size of the pins needs to be reduced but if very fine pins are used they have a tendency to break. A further problem with very small holes is that they can become blocked, particularly if the liquid to be dispensed is a lacquer or the like.

There is a need therefore, for a pressurised dispenser valve which overcomes, or at least mitigates, some or all of the problems associated with the known valves.

In accordance with a first aspect of the invention, there is provided a pressurised dispenser valve, the valve having a valve housing with at least one fluid inlet though which a fluid present in an associated dispenser may pass to enter the valve housing, the fluid inlet being formed at least partly by or in a resiliently deformable portion of the valve housing, the deformable portion being arranged such that, in use when the valve is opened, it deforms from an initial resiliently biased configuration in which the fluid inlet has an initial cross sectional area to a deformed configuration in which the fluid inlet has an altered cross sectional area in response to a pressure differential between the interior of the housing and the exterior of the housing.

The resiliently deformable portion may be configured such that cross-sectional area of the fluid inlet may be reduced or increased in response to a pressure differential between the interior of the housing and the exterior of the housing when the valve is opened.

The resiliently deformable portion may be configured such that the amount by which the cross sectional area of the fluid inlet alters when the valve is opened in use varies in dependence on the pressure in the associated dispenser.

Because the change in cross sectional area of the inlet can be made to vary independence on the pressure in the canister, this arrangement can be used to control the rate of flow of the fluid through the inlet as the pressure in the canister falls during use.

The resiliently deformable portion may be configured such that, in use, the rate of flow of the fluid through the inlet varies in dependence on the pressure in the associated dispenser.

The resiliently deformable portion may be configured such that, in use, the rate of flow of the fluid through the inlet is maintained substantially constant as the pressure in the associated dispenser falls over its useful life.

The resiliently deformable portion may be configured such that, in use, the rate of flow of the fluid through the inlet is increased as the pressure in the dispenser falls over its useful life.

The resiliently deformable portion may be configured such that the rate of flow of the fluid through the inlet is decreased as the pressure in the associated dispenser falls over its useful life.

The fluid inlet may comprise at least one opening which is at least partly defined by or formed in the resiliently deformable portion, the, or each, opening having an initial cross sectional area when the resiliently deformable portion is in its initial resiliently biased configuration, the arrangement being such that in use, deformation of the resiliently deformable portion when the valve opens causes the, or each, opening to be partially closed so as to have an effective cross sectional area which is less than its initial cross sectional area.

The housing may have a rigid main body portion formed from a substantially rigid polymeric material, the resiliently deformable portion being formed, at least in part, by means of a resiliently deformable polymeric material over-moulded onto the rigid portion. In which case, the, or each, opening may be formed in the resiliently deformable polymeric material. The, or each, opening may be elongate. The, or each, opening may be in the form of a slit in the resiliently deformable polymeric material. The, or each, slit may be located near an edge of the resiliently deformable portion proximal to the rigid main body portion. An outer surface of the deformable portion is shaped such that it does not conform to the profile of the rigid main body portion.

The valve may be configured so that, in use, the rate of flow of the fluid through the inlet is increased suddenly when the pressure in the dispenser falls to a predetermined value. The valve may be configured so that the amount by which the cross sectional area at least one opening is reduced when the valve is opened reduces suddenly when the pressure in the dispenser falls to a predetermined value. At least one further inlet opening may be at least partly defined by or formed in the resiliently deformable portion, the valve being configured such that, in use, when the pressure in the canister is above the predetermined value the at least one further opening is substantially closed when the valve is opened.

The valve housing may comprise a substantially rigid main body portion and a sleeve mounted to the main body portion, the sleeve comprising the resiliently deformable portion. In which case, the sleeve may be formed entirely from a resiliently deformable polymeric material or the sleeve may comprise a rigid portion formed from a substantially rigid polymeric material onto which is over-moulded a resiliently deformable polymeric material. The fluid inlet may comprise an opening formed in a resiliently deformable portion of the sleeve. The sleeve may have a groove on an inner surface, the fluid inlet being formed, at least in part, between the groove and an opposing surface of the rigid main body portion of the valve housing.

The resiliently deformable portion may have at least two walls or surfaces arranged at an angle to one another, the fluid inlet being formed at least partly by or in one of the walls or surfaces. The walls or surfaces may be arranged at an angle to one another in the range of 70 to 110 degrees, or in the range of 80 to 100 degrees, or in the range of 85 to 95 degrees.

The resiliently deformable portion may be shaped to provide at least one indentation. The resiliently deformable portion may be shaped to provide at least one protrusion.

The valve housing may have two of said fluid inlets, a first fluid inlet through which a propellant gas in an associated dispenser can enter the housing to be mixed with a liquid product as it is dispensed and a second fluid inlet through which a liquid product present in the associated dispenser enters the valve housing. The gas inlet may be formed at least partly in or by a first resiliently deformable portion of the housing and the liquid inlet may be formed at least partly by or in a second resiliently deformable portion of the housing. The first and second resiliently deformable portions may be configured such that, in use, the ratio of gas to liquid in the product as it is dispensed increases as the pressure in the dispenser falls. The first and second resiliently deformable portions may be configured such that, in use, the ratio of gas to liquid in the product as it is dispensed suddenly increases when the pressure in the dispenser falls to the predetermined value. The first resiliently deformable portion may comprise a side wall region of the valve housing. The valve housing may have a spigot for mounting a dip tube and the second resiliently deformable portion may be located at a distal end region of the spigot. The second resiliently deformable portion may be frusto-conical in shape, comprising one or more openings in a tapered side wall region.

The valve may be configured such that, in use, the gas and liquid are mixed inside the valve housing or the valve may have separate flow paths for the gas and liquid.

The valve may be designed to minimise dead space. The valve may have a valve stem having a bore, and a rod, tube or similar member may be inserted into the bore to reduce the dead space. The valve may have a valve stem having a bore and one or both of the valve housing and the stem may be at least partially filled with beads or the like to minimise the dead space.

In accordance with a second aspect of the invention, there is provided a pressurised dispenser valve, the valve having a valve housing comprising two fluid inlets, a first inlet through which a gaseous propellant present in an associated dispenser can enter the housing to be mixed with a liquid product and a second inlet through which a liquid product present in an associated dispenser can enter the valve housing, the valve housing having a main body portion formed from a substantially rigid polymeric material and two resiliently deformable portions each formed from a resiliently deformable polymeric material over-moulded on to the rigid portion, the gas inlet comprising one or more openings in a first of the resiliently deformable portions, the liquid inlet comprising one or more openings in a second of the resiliently deformable portions, each of the first and second resiliently deformable portions being configured such that, in use when the valve is opened, it deforms from an initial resiliently biased configuration in which the, or each, opening has an initial cross sectional area to a deformed configuration in which the, or each, opening has a reduced cross sectional area in response to a pressure differential between the interior of the housing and the exterior of the housing.

Each of the first and second resiliently deformable portions may be configured such that the reduction in cross sectional area of the, or each, opening is a function of the pressure in the associated dispenser. Each of the first and second resiliently deformable portions may be configured such that, in use, the ratio of gas to liquid product dispensed increases as the pressure in the associated dispenser decreases over the useful life of the dispenser.

In accordance with a third aspect of the invention, there is provided a valve for a pressurised dispenser, the valve having a valve housing and a valve member mounted in the valve housing for movement between valve closed and valve open positions, the valve housing having a liquid inlet through which a liquid product present in an assisted dispenser can enter the valve housing to be dispensed and a gas inlet through which a gaseous propellant present in an associated dispenser can enter the housing to be mixed with a liquid product, the valve also comprising and outlet nozzle mounted on a valve stem, the stem having a passage through which the mixture of liquid product and gas can flow from the valve housing to the nozzle, in which the valve is designed to minimise dead space.

The valve may comprise a rod, tube or the like positioned in the flow passage in the stem. The rod, tube or the like may be provided as a part of the valve nozzle.

The valve may comprise a mesh or filter in the flow passage of the stem.

The valve housing and/or the valve stem may be at least partially filled with beads or the like.

In accordance with a fourth aspect of the invention, there is provided a pressurised dispenser having a valve in accordance with any of the first, second, or third aspects of the invention.

Several embodiments of the invention will now be described, by way of example only, with reference to the following drawings in which:

FIG. 1 is a perspective cross sectional view through a first embodiment of pressurised dispenser valve in accordance with the invention shown mounted in cup portion of a pressurised dispenser;

FIG. 2 is a view similar to that of FIG. 1 of a second embodiment of pressurised dispenser valve in accordance with the invention shown mounted in cup portion of a pressurised dispenser;

FIG. 3 is a perspective view of a housing forming part of the dispenser valve of FIG. 2;

FIG. 4 is a perspective view of a modified form of the housing of FIG. 3;

FIG. 5 is a cross-sectional view of a modified deformable spigot end portion for use with a valve in accordance with the invention;

FIG. 6 is a view similar to that of FIG. 5 of a further modified deformable spigot end portion for use with a valve in accordance with the invention;

FIG. 7 is a view similar to that of FIG. 1 but of a third embodiment of pressurised dispenser valve in accordance with the invention shown mounted in cup portion of a pressurised dispenser;

FIG. 8 is a perspective view of part of a housing forming part of a valve in accordance with the invention, illustrating ways in which the deformable portion may be shaped to control the rate of flow of gas through a VPT inlet; and

FIG. 9 is a perspective cross-sectional view of a valve housing with an adaptor sleeve form part of a further embodiment of a pressurised dispenser valve in accordance with the invention.

The same reference numerals but increased by 100 in each case will be used to denote features having the same or equivalent function in the following embodiments.

A first embodiment of a male type dispenser valve 10 is shown in FIG. 1. The valve 10 has a hollow plastic housing 11 mounted in a metal cup 12, which forms part of an upper surface of a pressurised dispenser such as an aerosol canister. As is well known in the art, the dispenser canister will typically contain a liquid product, which may be a liquor, gel or the like, to be dispensed and a propellant, at least part of which is present as a gas above the liquid product. The propellant pressurizes the canister so that the product is dispensed when the valve is opened. Any suitable propellant may be used such as butane, compressed air, nitrogen or carbon dioxide, for example. However, the invention is particularly advantageous for use with dispensers in which the propellant is available exclusively or mainly as a compressed gas, such as compressed air, nitrogen or carbon dioxide or with other reduced VOC formulations.

A sealing gasket 13 is located in a recess 11 a at the upper end of the housing, an outer diameter portion of the gasket being clamped between the cup 12 and a base of the recess. A valve member 14 is slidably positioned inside the housing and is biased upwardly by means of a spring 15. An integral valve stem 16 projects outwardly from the valve member. A lower end of the housing 11 is formed into a spigot 17 which provides an inlet to the valve. A dip tube 18 is mounted to the spigot 17 in a conventional manner. The valve stem 16 is hollow, having a blind axial fluid passage 19 extending from the upper surface of the stem into the body of the valve member. A lateral fluid passage 20 extends from a lower end of the axial passage 19 and opens into a recessed outer circumferential region 21 of the valve member. When the valve is closed, as shown in FIG. 1, the gasket 13 engages in the recessed region 21 to seal the opening of the lateral passage 20. This prevents fluid inside the housing 11 from entering the lateral passage 20 and exiting the valve through the axial passage 19.

An actuator/nozzle (not shown) will usually be mounted to the upper or distal end of the stem 16 in a manner well known in the art. The actuator/nozzle will usually comprise an atomising nozzle arranged so that the fluid passing through it when the valve is opened is broken into droplets or atomized to form a spray. However, in some applications, the actuator/nozzle may be configured to dispense the product as foam.

When the dispenser valve 10 is not being actuated, the valve member 14 is biased by the spring 15 to its upper or closed position, as shown in FIG. 1, so that the lateral passage is 20 is sealed by the gasket 13 and the valve is closed. To actuate the dispenser, pressure is applied to the actuator/nozzle so that the valve member 14 is moved inwardly, or downwardly as shown, in the housing against the bias of the spring 15 until the recessed region 21 and the opening of the lateral passage 20 becomes exposed below the gasket 13. The liquid product is then forced by the pressure in the canister through the lateral passage 20 and the axial passage 19 in the stem 16 from where it enters an outlet passage of the actuator/nozzle to be dispensed through one or more outlet orifices of the actuator/nozzle. When the downward pressure applied to the actuator/nozzle is removed, the spring 15 once again biases the valve member 14 upwardly to the position shown in FIG. 1 to close the valve.

The valve housing 11 has a main body portion 23 which is formed of a first substantially rigid polymeric material and has two resiliently deformable portions or regions 24, 25 which are each formed, at least partly, of a polymeric material which is resiliently flexible in comparison with the first rigid material. Preferably, the valve housing is injection moulded using a bi-injection technique in which the main body portion is moulded from a first material in a first injection phase and the two deformable regions 24, 25 are formed in a second injection phase in which the resiliently flexible plastics material is over-moulded onto first rigid material. The two deformable regions 24, 25 will usually be formed of the same material but they could be formed of different materials. The substantially rigid portion may be made of a rigid plastics material such as polypropylene or nylon plastic, for example. The resiliently deformable regions may be formed from a relatively flexible plastics material such as TPE, TPV, pr a flexible polypropylene, for example.

The expression “rigid plastic material” is used herein to refer to a plastic material that possesses a relatively high degree of rigidity and strength once moulded into the desired form.

The term “flexible plastic” is used herein to denote plastics materials which are inherently flexible/resiliently deformable once moulded into the desired form. Such materials are used, for example, in the preparation of shampoo bottles or shower gel containers.

A first of the deformable regions 24 forms part of a side wall 26 of the housing. The first deformable region 24 has an opening or hole 27 which forms a fluid inlet or VPT through which propellant gas present in the canister above the liquid can pass into the housing to mix with the liquid product when the valve 10 is open. The other deformable region 25 extends across the lower end of the spigot 17 and also has an opening or hole 28, which forms a further fluid inlet through which the liquid product passes to enter the valve housing when the valve is open.

When the valve 10 is closed, the pressure inside the housing will be the same as the pressure within the canister but outside of the housing. However, when the valve is opened, the interior of the valve is connected with atmosphere via the stem passages 19, 20 so that the pressure inside the valve housing 11 is reduced. This results in a pressure differential between the inside of the housing and the outside of the housing, the magnitude of which is a function of the pressure in the canister.

The deformable regions 24, 25 are arranged so as to deform or distort when the valve is opened to vary the cross-sectional area of the openings 27, 28 when subjected to the pressure differential. When the valve 10 is closed and there is no pressure differential between the inner and outer surfaces of the housing, the deformable regions 24, 25 adopt an initial, resiliently biased configuration in which the respective openings therein 27, 28 have an initial cross-sectional area. When the valve is open, each of the deformable regions 24, 25 are configured so as to deform or distort due the difference in pressure acting on their inner and outer surfaces in such a way that the cross-sectional area of the respective opening 27, 28 is reduced when compared to its initial cross-sectional area. Furthermore, the deformable regions 24, 25 are also configured so that the amount by which the cross-sectional area of the respective openings 27, 28 are reduced varies in dependence on the magnitude of the pressure differential. Thus, by appropriate design, the deformable regions 24, 25 and their openings 27, 28 can be arranged to act as flow control mechanisms to regulate the rate of flow of liquid through the valve and the rate of flow of propellant gas into the liquid in dependence on the pressure in the canister.

In a particularly preferred embodiment, the deformable regions 24, 25 are arranged so that the ratio of gas to liquid dispensed increases as the pressure in the canister falls over the useful life of the dispenser. Those skilled in the art will appreciate that there are numerous ways in which this can be achieved. For example, the second deformable region 25 can be configured to maintain the rate of flow of liquid through the valve 10 substantially constant over the useful life of the dispenser whilst the first deformable region 24 is configured so that the rate of flow of gas into the valve housing 11 through the opening 27 increases as the pressure in the canister falls. Alternatively, the second deformable region 25 can be configured so that the rate of flow of liquid through the valve decreases as the pressure in the canister falls. Typically the reduction in the rate of flow of the liquid through the open valve over the useful life of the dispenser will be anything up to about 30%. With this alternative arrangement, the first deformable region 24 can be configured to maintain the rate of flow of propellant gas into the valve housing 11 substantially constant as the pressure falls or it can be configured so that the rate of flow of the gas increases.

In order to increase the rate of flow of gas into the housing 11 as the pressure in the canister falls, the first deformable portion 24 is arranged so that the cross-sectional area of the opening 27 when the valve is open increases non-linearly as the pressure in the canister falls. This can be achieved by profiling the opening and/or the deformable region around the opening so that the opening is distorted in a non-linear way with pressure. One way to achieve this is to make the opening 27 an ellipse whose major axis extends laterally or horizontally. When the canister is at full pressure, the opening will be almost fully closed when the valve is open but as the pressure falls the opening will close less in the vertical direction so that the cross-sectional area of the opening when valve is open increases by a larger amount for a given drop in pressure than would be the case with a round hole, for example.

Whilst in the embodiment described each of the deformable regions 24, each has a single opening 27, 28 it will be appreciated that in this, or any of the other embodiments to be described, either or both of the deformable regions can have more than one opening 27, 28. For example, in certain applications it is desirable to have a sudden, possibly step function, increase in the flow rate of the propellant gas through the VPT when pressure in the canister falls to a low pressure, which may be in the region of 0.4 to 0.5 MPa (4-5 bars) for example. This will typically equate to a situation in which approximately 90% of the liquid contents of the canister have been used up. Such a sudden increase can be achieved by having a second or further VPT opening in the first deformable region 24 which is closed, or substantially closed, when the valve is opened until the pressure in the canister falls to a pre-determined level, which may be in the range of 0.4 to 0.5 MPa. Once the pressure has fallen to or below the predetermined value, the further VPT opening is at least partially open when the valve is opened so that an additional flow path is provided into the housing. Such an increase in flow through the VPT is particularly useful where the propellant gas is air and a significant increase in the ratio of air to liquid is required at low pressures to maintain the quality of the spay. It will be appreciated that shape and position of the further opening and the shape and configuration of the first deformable portion 24 can all be manipulated so that the further VPT opening only opens at the desired pressure. Alternatively, the first deformable portion 24 and the opening 27 may be configured so that the cross sectional area of the VPT opening 27 when the valve is open increases suddenly, or as a step function, when the pressure in the canister falls to or below the predetermined valve, which again may be in the range of 0.4 to 0.5 MPa.

Depending on the nature of the material used, the deformable regions 24, may be compressed when subjected to pressure, the higher the pressure the greater the degree of compression. This can be a problem when used in a pressurised dispenser as the compressed material may loose its elasticity over time making it difficult to predict how it will react as the pressure reduces. This problem can be made worse in aerosol dispensers because many of the chemicals used may also react with the material and the dispensers may not be used for many years and may be used in differing climates. It is, therefore, preferable if the deformable regions 24, 25 are arranged to flexibly deform by bending or distorting to vary the cross-sectional area of the openings 27, 28 rather than relying on compression of the material. However, in some applications, in may be possible to use the relative compression of the material as the pressure falls to vary the cross-sectional area of the opening or openings to control the flow rate. For example, an inlet opening can be provided in a relatively thick section of material so that at high pressures the material is squashed with some of the material deforming in to the opening to partially close it.

The deformable regions 24, 25 can be made in any suitable deformable shape including a flat or a domed or dished shape with an opening in or near the centre. A particularly advantageous arrangement is to shape each deformable region 24, 25 so that it has at least two walls or surface regions arranged at an angle to one another with the opening or openings 27, 28 in a first of the walls or surface regions. The walls or surface regions are arranged so that pressure acting on the second of the walls or surface regions when the valve is opened helps to deform the first wall or surface region to close the opening or openings. The walls or surface regions may be angled at anywhere from 70 to 110 degrees to each other but are more preferably angled at anywhere from 80 to 100 degrees to each other and more preferably still are angled at anywhere from 85 to 95 degrees to each other. At least part of the second wall or surface region could be made of a substantially rigid material.

FIG. 2 shows a second embodiment of a valve 110 in accordance with the invention in which the first and second deformable regions 124, 125 have angled walls or surface regions as described above. The valve 110 is similar to the first embodiment except that it is a divided valve in which the gas and liquid flow through the valve along separate flow paths to be mixed in a nozzle (not shown). The valve 110 thus has a second sealing gasket 130 spaced below the upper gasket 113 at an upper end of the spigot 117 within the housing. The valve member 114 has a downwardly extending axial projection 131, the lower end of which locates within the lower gasket 130. The axial passage 119 in the valve member extends along the axial projection and connects with the lateral passage 120 near the lower end of the projection 131. The arrangement is such that when the valve member is in its upper, closed position, the opening of the lateral passage 120 is sealed by the lower gasket so that liquid product is unable to enter lateral passage to exit the valve via the axial passage 119.

The valve member 114 has a further axial passage 132 along which propellant gas can pass from an upper section 111 a of the housing to enter the nozzle. The further axial passage 132 will be referred to as the axial gas passage 132 and the first axial passage 119 will be referred to as the axial liquid passage. The axial gas passage extends through a larger diameter region of the stem 116 parallel to the axial liquid passage 119. The axial gas passage opens at its lower end into the annular recessed region 121 and is sealed by the upper gasket when the valve member is in its upper, closed position to prevent propellant gas from entering the passage 132.

When the valve 110 is actuated, downward pressure is applied to an actuator/nozzle (not shown) mounted to the upper end of the stem 116 to move the valve member inwardly, or downwardly as shown, so that the lower end region of the projection 131 is moved below the lower gasket seal to enable the liquid product to flow through the lateral and axial liquid passages 120, 119 to be dispensed. At the same time, the open lower end of the gas passage 132 is moved below the upper gasket 113 so that propellant gas can flow through the axial gas passage 132 and into a nozzle (not shown) where it is mixed with the liquid. When the pressure is removed from the actuator/nozzle, the spring 115 biases the valve member upwardly to the position shown in FIG. 2 to close the valve.

The lower gasket divides the interior of the housing into two sections, the upper section 111 a into which propellant gas can enter via the VPT opening 127 in the first deformable region 124 and a lower section 111 b into which the liquid product can enter via the opening 128 in the second deformable region 125. In the present embodiment, the lower gasket 130 is formed integrally with the first deformable region 124 but this need not be the case. The lower gasket has a though bore 133 with an upper region 133 a which engages with the outer surface of the valve member projection 131 to form a seal therewith. A lower region of the bore is frusto-conical in shape, tapering outwardly in a downward direction. When the valve member 114 is depressed to actuate the dispenser, the lower end region of the projection 131 enters the conical portion of the bore so that liquid is able to enter the lateral liquid passage 120 whist the gasket continues to form a seal about the projection 131 above the lateral passage 120 to prevent liquid from entering the upper section of the housing or the propellant gas entering the lower section.

In a modification to the arrangement show, the lower gasket 130 could be adapted to form a spring for the valve member 114, in which case the spring 115 can be omitted.

As best seen in FIG. 3, the first deformable region 124 has a side wall 134 and a lower wall 135 which extends at approximately 90 degrees to the side wall 134. In this embodiment, the VPT opening 127 is formed in the side wall. When the valve is opened, the pressure differential acting on the lower wall 135 forces the wall upwardly, as shown in FIG. 2, helping to compress or distort the side wall so as to close the opening 127. In this arrangement, the lower wall could be formed at least partly of a rigid material. The second deformable region 125 has a frusto-conical shape with a tapered side wall surface 136 in which the liquid inlet opening 128 is located and a generally flat lower end wall 137. When the valve is opened, the pressure of the liquid acting on the outer surface of the lower end wall applies an upward force tending to compress or distort the tapered side wall region and so close the liquid inlet opening 128. The lower end wall 137 can be rigid or flexible.

FIG. 4 illustrates an alternative embodiment of the housing 111 in which the opening 127 in the first deformable region 124 is provided in the lower wall region 135. In this arrangement, pressure acting on the side wall region 134 when the valve is open helps to compress or distort the lower wall 135 to close the opening 127. The opening 127 in this embodiment is formed gas an ellipse having a major axis extending laterally of the valve housing.

FIGS. 5 and 6 illustrate slightly modified embodiments of the second deformable region 125 of the housing 111. FIG. 5 shows an embodiment, in which there are two openings 128 a, 128 b through the tapered side wall region. As shown, the openings 128 a, 128 b can be of different sizes. In the embodiment shown in FIG. 6, the lower end wall 137 is dished inwardly on its outer surface to change the way in which the region deforms or distorts when the valve opens. These embodiments illustrate some of the different ways in which the deformable regions can be adapted to provide the required flow characteristics of the valve. It will be appreciated that may differing ways of modifying the deformable regions can be used to achieve the desired effects.

Pressurised dispensers are intended to be operated in a generally upright orientation as shown in FIGS. 1 and 2. In this orientation, the liquid product occupies the lower, bottom end of the container and is drawn through the dip tube into the valve. However, if the dispenser is inverted, the propellant gas will move to the bottom end of the canister, which is now uppermost, and significant proportions of propellant gas will be lost through the valve if it is actuated. To prevent this loss of propellant gas, some dispenser valves are fitted with arrangements that close of the liquid inlet to the valve when inverted. Thus the valve 110 shown in FIG. 2 has a ball bearing 139 located within the spigot 117. When the valve is inverted, the ball 139 seals against a flexible washer or seal 140 to prevent propellant gas from being lost if the dispenser is actuated whilst inverted. During normal operation, the force of the liquid entering the spigot 117 is sufficient to lift the ball bearing off its lower seat 142 to allow the liquid to pass but without pressing the ball into contact with the seal 140.

Whilst the ball bearing 139, 229 is intended primarily to prevent loss of the propellant gas when the dispenser is actuated in an inverted condition, it also acts to prevent the lower portion of the spigot and the dip tube from filling with propellant gas when the dispenser is not in use but is in an upright position. Without the ball valve 139, the propellant gas will tend to enter the valve and the dip tube through the VPT to push the liquid in the valve and dip tube down until it is equal with the level of the liquid in the rest of the canister. This results in a significant amount of propellant gas being wasted when the valve is first opened. With the inversion ball valve arrangement, the ball sits on the lower seat 142 sealing off the dip tube which prevents the gas from entering the valve when the valve is closed. A further seal can be provided at the lower seat if desired. A further embodiment of a valve 210 in accordance with the invention is shown in FIG. 7. The valve 210 is similar to the previous embodiment except that the seal 240 for the ball bearing 239 is formed integrally as an extension of the lower gasket 230. Thus, the lower gasket 230 is extended downwardly to form an O ring type seal 240 about the inner bore of the spigot above the ball bearing. If the dispenser is inverted whilst it is being actuated, the ball bearing will form a seal with the O ring 240 to prevent propellant gas from being lost through the valve. In order to assemble the valve, the ball bearing 239 can be inserted through the lower gasket 230 which will deform.

Whilst the inversion ball valve arrangements 139, 239 described above are effective at prevent loss of the propellant gas when the dispenser is inverted, it is possible a loss of propellant gas could occur if the valve 10, 110, 210 is opened when the dispenser is only partially inverted. If the valve is opened whilst the dispenser is tilted such that the free end of the dip tube is not submerged in the liquid, so that no liquid is drawn into the valve, but whilst the propellant gas still surrounds the VPT opening, then a large amount of the propellant gas will be dispensed as the gas flow through the VPT will not have to compete with the liquid flow. To overcome this problem, a ball type inversion valve can be provided downstream of the VPT. In an undivided valve, such as that shown in FIG. 1, an inversion valve could be located in the valve stem 19 or in the nozzle, for example. In a divided valve such as that shown in FIGS. 2 and 7, two inversion valves can be provided, one in the normal gas flow path and one in the normal liquid flow path. For example, a further inversion valve can be provided in the gas passage 132, 232 or in the nozzle in addition to the inversion valve 139, 239 positioned as shown in FIGS. 2 and 7. Alternatively, the dispenser could be provided with a device which enables liquid to be dispensed even when the dispenser is inverted. This can include any of the devices disclosed in the applicant's International patent published as WO 2004/022451, the contents of which are hereby incorporated by reference.

As shown in FIG. 7, the opening 227 in the first deformable region is provided in the side wall 234 but it could be provided in the lower end wall 235 instead. Indeed, any of the arrangements described in any of the embodiments can be used in any of the other embodiments described.

In the embodiments described above, the first deformable region 24, 124, 224 has been provided in a side wall region of the housing. Whilst this is a convenient location, it should be appreciated that the first deformable region can be provided in any suitable location on the valve housing. Similarly, the second deformable region 25, 125, 225 need not necessarily be located at the inlet end of the spigot, though this is a particularly advantageous position.

Where a valve in accordance with the invention is to be used with a dispenser having a propellant in the form of a compressed gas, such as air or nitrogen, and especially when the liquid flow rates is low, e.g. under 0.6 g/s, the VPT openings 27, 127, 227 need to be extremely small, sometimes having a cross sectional area equivalent to a 0.15 mm diameter hole. Producing such small openings is difficult, particularly in large scale manufacture. If the opening is formed by pushing a pin through the material, there is a tendency for the pin to break owing to its small size. There is also a risk that such a small opening can become partially or totally blocked in use. In order to overcome these difficulties, it has been found to be particularly advantageous if the opening, or openings where more than one is required, is produced a very fine slit.

Any suitable method of forming the slit can be used. In one method a pin having a length roughly equal to desired length of the slit but which has a thickness larger than that desired in the final slit is inserted through the resilient material shortly after it has been moulded. This can be carried out in the mould tool or shortly after the valve body has been removed from the mould tool. When the pin is removed, the flexible material tends to reform and closes the opening to leave a fine slit. In one example, a pin of 0.9 mm in length and 0.7 mm depth was used to produce a slit having dimensions of about 0.9 mm×0.05 mm or less. The ability to use a pin which is thicker than the actual slit reduces the tendency for the pin to break or be deformed. Another method of producing a slit is to expose the area of the material in which the slit is to be formed in the mould and to blow compressed air, or another gas, through the material to form the slit. A moving pin in the mould can be used to expose the area of material. In some instances, it may be possible to form the slit as part of the moulding process.

A fine slit has been found to be easier to manufacture than an equivalent circular hole and is less likely to become blocked in use. The slit can be shaped so as to have curved side edges, in which case it acts in a similar manner to the elliptical openings discussed above. Thus when the valve is opened, the flexible material is pushed inwardly tending to close the opening but the material can also be acted upon so as to move apart vertically across the slit. By balancing these actions, greater control can be achieved over the change in cross sectional area of the opening as the pressure in the canister falls.

Where the VPT opening 27, 127, 227 is provided in the form of a slit, it has been found to be advantageous to position the slit in the middle of an edge of the resilient material but close to the rigid main body portion 23, 123, 223, of the housing, as indicated schematically by the dashed line 127 a in FIG. 3. The slit 127 a can be positioned adjacent any edge of the resilient material but has been found to be particularly effective when positioned adjacent the upper edge as shown in FIG. 3. If the slit is positioned close the centre of a wall 134 of the flexible material, there is a risk that the slit may be pushed inside out at high pressure allowing too large a flow of gas.

The liquid inlet openings 28, 128, 228 could also be provided in the form of a slit.

The rate of flow through the VPT opening(s) 27, 127, 227 and the change in flow rate as the pressure in the dispenser falls can all be affected by the shape of the deformable region 24, 124, 224 itself as well as the shape and size of the opening(s). In the arrangements shown FIGS. 1, 2, 3, 4 and 7, the deformable region 24, 124, 224 in which the VPT openings are provided is shaped so as to substantially follow the shape and profile of the rigid portion 23, 123, 223 of the housing. However, this need not be the case and the deformable portion can be shaped in any suitable way to provide the required control of the flow rate through the VPT openings. For example the deformable portion may be indented or have parts which project outwardly or a combination of the two. FIG. 8 illustrates this principle. The drawing shows part of a housing body 211′ having a deformable region 224′ which is shaped to provide an angled indentation with number of ridges and troughs. This is an example of how the deformable portion might be shaped in a way which does not follow the contour or profile of the rigid portion 233 of the housing.

The shape and profile of the deformable region, the material properties of the deformable portion and the shape, size and positioning of the opening can all affect the rate of flow through the VPT opening(s) 27, 127, 227 when the valve is opened and the change in flow rate as the pressure in the dispenser falls. Thus a designer can manipulate all of these parameters to achieve the desired control of the flow rate. The same is also true of the deformable regions 25, 125, 225 and the liquid inlet openings 28, 128, 228.

Whilst it is advantageous for the deformable regions to be formed integrally as part of the housing, a similar effect can be achieved by using a sleeve or adaptor which fits over the rigid main body portion of the housing and which has deformable regions that align with suitable openings in the rigid portion. An example is illustrated in FIG. 9 which shows a sleeve or adaptor 350 mounted to the spigot 317 of a valve housing main body 311.

In the embodiment shown in FIG. 9, the housing main body 311 is formed entirety of rigid plastics material and the sleeve 350 is formed at least partly from a resiliently flexible plastics material. The sleeve has an annular main body region 351 which is a tight sliding fit on the spigot 317 of the valve housing 311. The sleeve also has a smaller diameter extension 352 projecting axially downwardly from the main body portion 351 and which forms a spigot to which a dip tube may be fitted. A hollow bore 353 extends axially through the spigot and is fluidly connected with the interior of the main body region 351. The lower end 325 of the sleeve spigot 352 is frusto-conical in shape and an opening 328 is formed through the side wall of the conical region to provide a fluid inlet into the bore 353 of the sleeve and hence to the interior of the valve housing 311. The conical end portion 325 of the sleeve spigot is resiliently and flexibly deformable and acts in a similar manner to the second deformable regions 25, 125, 225 of the previous embodiments described above to vary the rate of flow of liquid through the valve in dependence on the pressure in the canister.

An opening 327 is formed through a side wall region of the main body region 351 of the sleeve near the top. The opening 327 leads into a groove 356 which extends downwardly along the inner surface of the sleeve to a position below the lower end of the valve housing spigot 317. The opening 327 and groove 356 form a fluid inlet or VPT through which propellant gas in an upper region of the canister can flow to mix with the liquid entering the valve housing 311 when the valve is open. At least part of the side wall of the main body region 351 in the vicinity of the opening 327 and groove 356 is resiliently flexible and is arranged to deform or distort when the valve is opened to restrict the flow of gas through the opening and/or groove in dependence on the pressure in the canister. For example, the side wall may deform inwardly in at least one point so that the minimum cross sectional area of the groove through which the gas flows is reduced when the valve is opened as a function of the pressure in the canister. The sleeve can be injection moulded entirely from a resiliently flexible polymeric material or it may be formed as a bi-injection moulding in which part of the sleeve is moulded in a first stage from a rigid polymeric material and the flexible portions are over moulded onto the rigid portions in a second moulding stage.

When the propellant gas is mixed with the liquid in the valve, as is the case in an undivided valve such as those shown in FIGS. 1 and 9, the gas forms bubbles in the liquid. Generally speaking, the finer and more homogeneous the bubbles formed are, the better the quality of spray produced at the nozzle. However, if there is too much dead space in the valve or the nozzle, the bubbles can expand and coalesce which may result in pulsing of the spray produced at the nozzle. The valve and nozzle should, therefore, be designed to reduce dead space to a minimum. The valve stem 19 is a particular problem in terms of dead space. In order to reduce the dead space in the valve stem, a tube or rod can be inserted into the bore. This could be a separate item inserted in the bore or it could be provided as a projection on the underside of a nozzle which locates on the upper end of the stem. For example, a small post may project from the underside of the nozzle into the valve stem 19 to reduce the dead space. The post could be shaped to ensure the gas and liquid remain mixed. In one arrangement, vertical grooves are provided in the outer surface of the post along which the gas/liquid mixture flows between the post and the walls of the stem. This arrangement can be used to provide a filter, preventing particles to large to pass along the grooves valve from entering and blocking the nozzle. This arrangement for forming a filter in a valve and nozzle combination may be claimed independently from the inventive concepts set out in the attached claims.

A filter or mesh could also be introduced into the valve stem and/or into the valve itself as a way of reducing dead space. An alternative arrangement would be to fill any areas such as the valve housing or valve stem where dead space may be an issue with small beads or the like. The beads would be dimensioned so as to be large enough not to block the valve or prevent movement of the valve components but would keep the bubbles small as they moved through the beads in the manner of a fluidised bed. This concept may be claimed independently of the main inventive concept claimed in claim 1. Pressurised dispensers are typically filled through the valve at high pressure and very quickly. To ensure the deformable regions are not blow out or deformed or that an adaptor sleeve is not blow off or displaced during the filling process, dispenser valves in accordance with the invention may be provided with a pressure relief valve which will open to enable the pressurised fluid to enter the canister. Any suitable valve can be used. In one particularly advantageous arrangement, a small slit is provided in one of the deformable regions or in the adaptor sleeve. During normal use, the pressure inside the canister will be sufficient to keep the slit closed at all times. During filling, the pressure of liquid and/or gas inside the valve housing or adaptor will be sufficient to open the slit up to enable the liquid and/or gas to enter the canister without damaging the deformable regions or displacing the adaptor sleeve.

In the embodiments described above, the deformable regions are arranged to vary the rate of flow of the gas and liquid in dependence on the pressure inside the canister and are preferably arranged to increase the ratio of propellant gas to liquid as the pressure in the canister falls. Whilst this is particularly advantageous, the invention can also be applied to dispenser valves in which the flow rate of only one of the gas or liquid is to be controlled. Thus a valve could have only a single deformable region similar to the first regions described above to regulate the flow of gas through a VPT. Alternatively, a valve could have only a single deformable region similar to the second regions described above to regulate the flow of liquid through the valve.

The invention can also be used to provide a fluid inlet to a pressurised dispenser valve without necessarily varying the flow rate of the fluid in dependence on the pressure. For example, it has already been discussed above that the use of very small VPT openings in the housing of a valve can be advantageous as they help the gas and liquid to mix and that producing such small openings in a rigid plastics housing is difficult. These problems can be overcome by providing the VPT openings in a deformable region in a manner similar to those previously described. Since the openings close up when the valve is opened, they can be produced with an initial size which is larger than that actually required and the deformable region configured so that the openings close to the desired size when the valve is opened. In this arrangement, the cross-sectional area of the openings when the valve is open may stay the same irrespective of the pressure in the canister.

The invention can also be used to provide a fluid inlet to the valve housing which is self cleaning. Since the openings in the deformable regions vary in size and shape when the valve opens and closes, any material that has become trapped in the openings will tend to become dislodged. In any event, material which clogs the openings when the valve is open and the openings are small will tend to fall away when the valve closes and the openings return to their larger initial size. Even if the material does move of its own accord, vigorous shaking of the canister should be sufficient to dislodge any such material.

When dispensing materials such as gels, for example, it is often necessary for the gel to be contained within a bag which is welded to the valve housing. In this arrangement, the propellant gas is held in the canister surrounding the bag. This is referred to in the art as bag-on-valve. Dispenser valves in accordance with the invention can be adapted for use in bag-on-valve dispensers. In this arrangement, the first deformable region will be positioned outside of the bag so that the propellant gas can enter the valve housing whilst the second deformable region would be located inside the bag.

It is a particular advantage that pressurised dispenser valves in accordance with the invention can be designed to be assembled and fitted to a dispenser using existing machinery used for conventional pressurised dispenser valves. Similarly, dispensers fitted with a valve in accordance with the invention can be filled using existing filling machinery. As a result, valves in accordance with the invention can be adopted with only relatively small capital outlay.

The invention can be adapted for use in dispensing a wide range of liquids of various viscosities, including but not limited to: antiperspirant sprays, deodorant sprays, perfumes, air fresheners, antiseptics, paints, insecticides, polish, hair care products, pharmaceuticals, water and lubricants, foams and gels.

Whereas the invention has been described in relation to what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed arrangements but rather is intended to cover various modifications and equivalent constructions included within the spirit and scope of the invention. For example, whilst the invention has been described in relation to male type dispenser valves in which the stem is integral with the valve member, the invention can be equally applied to female type dispenser valves in which the stem is integral with the actuator/nozzle. Furthermore, in the preferred embodiments, the valve is configured so that the flexible portion distorts when the valve is opened to close or partially close the inlet opening(s) formed therein as a result of the pressure differential across the valve housing. However, the arrangement could be reversed so that the, or each, opening is either closed or only very small in the initial state and is enlarged due to distortion of the flexible portion when the valve is activated. Where there are two flexible portions, one could be arranged so that the size of the inlet opening is decreased when the valve is activated and the other so that the size of the opening is increased.

Where the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof. 

1. A pressurised dispenser valve, the valve having a valve housing with at least one fluid inlet though which a fluid present in an associated dispenser may pass to enter the valve housing, the fluid inlet being formed at least partly by or in a resiliently deformable portion of the valve housing, the deformable portion being arranged such that, in use when the valve is opened, it deforms from an initial resiliently biased configuration in which the fluid inlet has an initial cross sectional area to a deformed configuration in which the fluid inlet has a reduced cross sectional area in response to a pressure differential between the interior of the housing and the exterior of the housing when the valve is open.
 2. (canceled)
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 4. A pressurised dispenser valve as claimed in claim 1, in which the resiliently deformable portion is configured such that the amount by which the cross sectional area of the fluid inlet reduces when the valve is opened in use varies in dependence on the pressure in the associated dispenser.
 5. A pressurised dispenser valve as claimed in claim 4, in which the resiliently deformable portion is configured such that, in use, the rate of flow of the fluid through the inlet varies in dependence on the pressure in the associated dispenser.
 6. A pressurised dispenser valve as claimed in claim 4, in which the resiliently deformable portion is configured such that, in use, the rate of flow of the fluid through the inlet is maintained substantially constant as the pressure in the associated dispenser falls over its useful life.
 7. A pressurised dispenser valve as claimed in claim 5, in which the resiliently deformable portion is configured such that, in use, the rate of flow of the fluid through the inlet is increased as the pressure in the dispenser falls over its useful life.
 8. A pressurised dispenser valve as claimed in claim 5, in which the resiliently deformable portion is configured such that the rate of flow of the fluid through the inlet is decreased as the pressure in the associated dispenser falls over its useful life.
 9. A pressurised dispenser valve as claimed in claim 1, in which the fluid inlet comprises at least one opening which is at least partly defined by or formed in the resiliently deformable portion, the, or each, opening having an initial cross sectional area when the resiliently deformable portion is in its initial resiliently biased configuration, the arrangement being such that in use, deformation of the resiliently deformable portion when the valve opens causes the, or each, opening to be partially closed so as to have an effective cross sectional area which is less than its initial cross sectional area.
 10. A pressurised dispenser valve as claimed in claim 9, in which the housing comprises a rigid main body portion formed from a substantially rigid polymeric material, the resiliently deformable portion being formed, at least in part, by means of a resiliently deformable polymeric material over-moulded onto the rigid portion.
 11. A pressurised dispenser valve as claimed in claim 10, in which the, or each, opening is formed in the resiliently deformable polymeric material.
 12. A pressurised dispenser valve as claimed in claim 11, in which the, or each, opening is elongate.
 13. A pressurised dispenser valve as claimed in claim 11 in which the, or each, opening is in the form of a slit in the resiliently deformable polymeric material.
 14. (canceled)
 15. (canceled)
 16. A pressurised dispenser valve as claimed in claim 9, in which the valve is configured so that the amount by which the cross sectional area of the at least one opening reduces when the valve is opened varies suddenly when the pressure in the dispenser falls to a predetermined value such that the rate of flow of the fluid through the inlet is increased suddenly.
 17. (canceled)
 18. (canceled)
 19. (canceled)
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 21. (canceled)
 22. (canceled)
 23. (canceled)
 24. (canceled)
 25. (canceled)
 26. (canceled)
 27. (canceled)
 28. (canceled)
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 30. A pressurised dispenser valve as claimed in claim 1, in which the valve housing has two of said fluid inlets, a first fluid inlet through which a propellant gas in an associated dispenser can enter the housing to be mixed with a liquid product as it is dispensed and a second fluid inlet through which a liquid product present in the associated dispenser enters the valve housing.
 31. A pressurised dispenser valve as claimed in claim 30, in which the gas inlet is formed at least partly in or by a first resiliently deformable portion of the housing and the liquid inlet is formed at least partly by or in a second resiliently deformable portion of the housing.
 32. A pressurised dispenser valve as claimed in claim 31, in which the first and second resiliently deformable portions are configured such that, in use, the ratio of gas to liquid in the product as it is dispensed increases as the pressure in the dispenser falls.
 33. A pressurised dispenser valve as claimed in claim 32, in which the first and second resiliently deformable portions are configured such that, in use, the ratio of gas to liquid in the product as it is dispensed suddenly increases when the pressure in the dispenser falls to the predetermined value.
 34. A pressurised dispenser valve as claimed in claim 31, in which the first resiliently deformable portion comprises a side wall region of the valve housing.
 35. A pressurised dispenser valve as claimed in claim 31, in which the valve housing has a spigot for mounting a dip tube and the second resiliently deformable portion is located at a distal end region of the spigot.
 36. A pressurised dispenser valve as claimed in clam 35, in which the second resiliently deformable portion is frusto-conical in shape, comprising one or more openings in a tapered side wall region.
 37. (canceled)
 38. A pressurised dispenser valve as claimed in claim 30, in which the valve has separate flow paths for the gas and liquid.
 39. (canceled)
 40. (canceled)
 41. (canceled)
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